Coil lifting and positioning mechanism



July 19, 1960 R. .1. BELER COIL LIFTING AND POSITIONING MECHANISM 3 Sheets-Sheet 1 Filed April 23, 1959 INVENTOR. Roas21' IBM:

y 1950 R. J. BELER 2,945,608

COIL LIFTING AND POSITIONING MECHANISM Filed April 25, 1959 3 Sheets-Sheet 2 2| \INVENTOR. ROBERT J. BELER A'r'rY.

July 19, 1960 R. J. BELER 2, 4

COIL LIFTING AND POSITIONING MECHANISM Filed April 23, 1959 3 Sheets-Sheet 3 INVENTOR. Rosem- 1651.52

Unit

2,945,608 COIL LIFTING AND POSITIONING MECHANISM The present invention relates to mechanism for lifting and transporting sheet metal stock in coil form, the coils being wound in convolute fashion to produce a series of laminatio'ns which are continuous throughout the coils and which produce, in the final shape of the coils, generally tubular integral laminated spool-like structures, the innermost convolutions of which define central bores which extend axially through the spools,

The handling of sheet metal coils of the character set forth above, either at the steel mill for loading purposes, or at a consumer location which a coil is distributed throughout the plan for unwinding at a punch press, for example, presents a problem due to the fact that the cylindrical shape of the coil makes it awkward and thus diflicult to handle' =It;is sometimes necessary to pick up such a coil when the same is supported with its longitudinal axis extending vertically, transport it to a different location and place it on a supporting surface with its axis extending horizontally. At other times, conversely, it is necessary to engage the coil when the same is in a horizontal position. Rresent day liftermechanisms have been provided with accessory devices which will enable them to handle coils of this general character for transportation from one place to another, but invariably, it is necessary that the coils be initially received or, engaged by the "lifter mechanism when they are supported either in a horizontal position o'r in a yertical pos'ition, and no provision is made for releasing the coils in any other position than the one in whichthey are received. Present day coil lifting devices are generally of the character shown and described in 'UnitedStates Patent tol looker et 'al., 'No. 2,841,434, granted on July 11, 1958 and entitled, Auxiliary Coil 'Liftin-g Device for the laws of a Sheet Lifter. I

The present invention is designed to overcome the above-noted limitation'that is attendant upon the construction and use of conventional coil lifting mechanism of the type shown in the above-mentioned patent to "Hooker 'et al., and toward'this end, it contemplates the provision of a novel lifter construction whereby ,thelifter may initially receive the coil in practicallyany portion of orientation, whether the coil bedispo'sed withits axis extending horizontally, with its axis extending vertically, or whether the coil be positioned at some'interrnediate angle, and which lifter, further, is capable of depositing the coil in any desired position, whether horizontal, vertical o'r otherwise.

The provision of acoiLlifter ofthe general character set forthabove being among the principal objects of the invention, it is a furtherobject to tprovidea rnechanism which is so .designedthat it may receivethe coil fin one given position .and deposit it .in a dilferent position i with the'transitionlbetween'the two coil positions taking place by an angular rnovement of the .coil about :an axis which is sninfiident-swith orwnot appreciably removed fromthe .oentenof rrmssofthe coil ,soflthat a minimum amount rnfitorqllerneedrby :applied'vto.the,coil:and to the coilsupporting structure which moves therewith as the coil is being turned.

Another object of the invention, ina positioning lifter of this character, is to provide a novelform of coilengaging clamping jaw mechanism including apair of cooperating clamping jaws adapted to engage a portion of a coil to be lifted therebetween, together with means whereby the clamping jaws may be initially brought-to preliminary clamping engagement with the eoil, and thereafter, when lifting force is applied to the lifter mechanism bodily as a whole, an additional degreeof clamping force is automatically applied to the clamping jaws, the amount of force so applied being proportional to the weight of the coil undergoing lifting so" that the heavier the cell, the greater will be the degree of clamping force applied to the latter. Numerous other objects and advantages of the invention not at this time enumerated will become more readily apparent as the following description ensues. In the accompanying three sheets of drawings forming a part of this specification, o'ne illustrative em bodiment of the invention has been shown. Y I In these drawings: 7

Fig. 1 is a sectional view taken substantially centrally and vertically through a coil lifting and positioning meetianism constructed in accordancewith the prin ciples the present invention'and showing'the same operatiyely applied to a coil which is disposed'in aiyertical position, the lifter being shown in the condition which it assumes immediately prior to the coil elevation operationf Fig. 2 is a sectional View similar to Fig f1 withthe coil lifter being shown in the condition which it assumes after the coil has been turned through an angle of and immediately prior "to release of the coilj w l V 3 is a .im i s eq ew t w l ts wi h certain parts being broken away to more cl early reveal the nature of the'inventio'n; Fig. 4 is a sectional view taken substantially along the line -4.4 of Fig. l; V f Fig. Sis a fragmentary'side elevational view ofa tractio'n hoist mechanisme'mploye'd in connection with 'the present invention; and s l Fig. 6 is an enlarged sectional view taken substantially along the line 6- 6 of-Fig. 4. I v Referring now -to thedrawings in detail andin par;- ticular to Figs. 1 to 3, inclusive, a lifter constructedin accordance with the principles of the present invention 'has been designated in its entirety at 10; The lifterdisclosed herein constitutes a preferred fornrof thefinyention and it is adaptedto'be attached to linemen in connection with the crane of an oyer h e ad hoist, the lifting hook of such a hoist being-designated at "12 The' l ter constitutes a medium or instrumentality for handl ng laminated sheet metal coils web as thecoil 14 in rnoving the coils from one location to another end in'so rnoving them, if desired, altering their position in space respect to .a horizontal-plane. 'l a I The coil 14 is of conventional design and eonsists of a single nnitary elongated stripof sheetngetal whichhas been wound in convolutefashion on a nrandrel'topro ee 'a series of adjacent convolutions 16 ,of the sheet niateri and the mandrel subsequently withdrawn so that spool-like article havinga central bore 1 8 extend'ng r h a r e s ie a substant l y yl n j Ia ate surface 20 and suhstajntiallygiiat:endjaces 2 1 are prod- Th lifter ha been d sign d 7 P ime q transporting such coils ironi one loc tiont another with the lifter receiving a coil in a verticallpo in aposition wherein one ofthe annularend rests squarely on a supporting'surface, andffor depos the coil either 'in the s ame position or in a position wherein-the cylindrical surface 20 thereo placed tangentially on a supporting surface at the time the coil is released. Alternatively, the lifter has been designed so that it may receive the coil in a horizontal position, transport it, and thereafter, release the same in a vertical position. It is within the scope of the present invention, however, that the lifter 10 may be employed for receiving a coil in any intermediate position as between the vertical position wherein it is illustrated in Fig. land the horizontal position wherein it is illustrated in Fig. 2 and for discharging the coil in the same or in any other intermediate position. Irrespective, however, of the particular use to which the present lifter construction may be put, the essential features of the invention are at all times preserved.

The lifter selected for illustration herein is comprised of three principal parts or assemblies including a selfcontained motor-driven assembly designated in its entirety at 22 and hereinafter referred to as the traction hoist assembly; a tiltable assembly designated in its entirety at 24 and hereinafter referred to as the tiltable lifter proper; and an interconnecting flexible medium which may be in the'form of a conventional compound roller chain assembly 26 by means of which the tiltable lifter proper 24 is suspended from the traction hoist assembly 22 for swinging movements about a horizontal axis in a manner that will be made clear presently.

The tiltable lifter proper 24 includes a pair of cooperating lifter jaws 32 and 34, respectively, the jaw 32 being fixed relative to the frame structure 36 and the jaw 34 being movable toward and away from the jaw 32 for coil-clamping and coil-releasing purposes, respectively. As best seen in Figs. 1 and 2, the jaw 32, which will hereinafter be referred to as the fixed jaw, is adapted to engage the outside cylindrical surface of the coil 14, while the jaw 34, which will hereinafter be referred to as the movable jaw, is adapted to engage the inside cylindrical surface of the bore 18 so that one side of the tubular coil 14 may be compressed and thus clamped between the two jaws 32 and 34 for coil-lifting and coilorientating purposes as will also be subsequently described.

The lifter assembly proper 24 involves in its general organization the previously mentioned casing or frame work 36 which, as shown in Fig. 3, includes a pair of spaced parallel side members 40 and 42 of generally F-shaped design and each of which includes a vertical leg 44 and upper and lower horizontal legs 46 and 48, respectively. The two side members 40 and 42 are maintained in their parallel spaced relation by means of intervening plates 50 which are welded along their side edges to the inside opposed faces of the side members in such a manner as to provide a substantially continuous, chain-winding drum surface, as will be described in detail presently. Chain guide rails 52 extend along the drum surface for chain centering purposes. Vertical struts or plates 53 extend between the distal ends of the legs 46 and 48 for reinforcing purposes.

A vertical plate 54 is welded to the edges of the vertical legs 44 of the side members 40 and 42 and constitutes the fixed jaw proper. The movable jaw 34 includes a pair of spaced parallel side plates 56 (Fig. 4) and a cross plate 57. The upper ends of the plates 56 carry transversely extending shafts 58 on which there are mounted rollers 60 adapted to ride on a pair of lower tracks on rails 62 Welded to the inside faces of the members 48. Upper rails 64 serve to confine the rollers 60 in channel-like guides 66. The guides 66 extend in a direction normal to the operative vertical face of the jaw plate 54 so that the movable jaw 34 is constrained to travel in a horizontal linear path as viewed in Figs. 1 and 3 toward and away from the fixed jaw 32.

The movable jaw 34 is adapted to be power-driven, which is to say that its movements toward and away from the jaw 32 are effected under the control of a reversible electric motor M1. The motor M1 is operatively mounted on a base 70 which extends across the upper edges of the two horizontal legs 48. The output shaft 71 of the motor M1 is operatively connected through a gear reduction device 72 to a torque limiting clutch 74 and the output shaft 76 of the clutch 74 carries a sprocket wheel 78. The sprocket wheel 78 is connected by means of a chain 80 to a second sprocket wheel 82 mounted on a feed screw or shaft 84 which extends longitudinally of the horizontal legs 48 and which is rotatably journalled in a bearing assembly 85 supported between the two horizontal legs 48. The feed screw 84 is threadedly received through a block or nut 86 which is interposed between and welded to the two vertical side plates 56 of the movable jaw assembly 34, provision being made for a certain amount of looseness or lost motion between the screw threads formed on the feed screw and the internal screw threads provided in the block 86 as shown in Fig. 7 and in a manner and for a purpose that will be made clear presently. It will be seen, therefore, that upon rotation of the motor shaft 71 in one direction or the other, the feed screw will be correspondingly rotated through a power train including the chain and sprocket mechanism 76, 78, 80, and the movable jaw 34 will be moved toward or away, as the case may be, from the fixed jaw 32. During such motion of the movable jaw 34, the rollers 60 will travel tractionally on the tracks or rails 62.

As will become more clear presently when the description of the operation of the present lifter construction is set forth, the motor M1 is employed for initially advancing the movable jaw 34 toward the fixed jaw to grip the cylindrical wall of the coil assembly 14 therebetween, as previously described. Means are further provided whereby after such initial gripping or clamping action of the jaw sections 32 and 34, upon lifting of the coil 14 from the surface on which it is supported, a further clamping action of the jaw sections will be effected under the influence of the combined weight of the lifter proper 24 and of the coil supported thereby.

Accordingly, as shown in Fig. 7, the adjacent threads 90 provided on the feed screw 84 are separated from each other by a distance greater than the width of the threads 92 provided on the not or block 86 so that the entire assembly including the block 86 and the movable jaw 34 to which it is affixed is possessed of a limited degree of axial movement relative to the feed screw. As will become clear presently, the block 86 has pivotally connected thereto the forked end of a link 94 and the other end of the link is connected to the chain assembly 26 in such a manner that the chain assembly will become effective when the lifter proper 24 is freely suspended by means of the chain assembly to exert a pulling force on the movable jaw assembly 34 in a direction tending to move the latter toward the fixed jaw 32.

The supporting chain assembly 26 is of conventional design and consists of an assembled series of alternate roller links and pin links and in which the pins are free to pivot within the bushings of the roller links with minimum clearance, thus permitting free articulation and lubrication. As best seen in Fig. 3, the roller chain 26 is of multiple link width. One end of the chain is firmly clamped as at to the casing or framework 36 near the lower end of the fixed jaw 32 and from thence the chain passes around a curved rail supporting member 102 upwardly along the vertical leg 44, and around a second curved rail-backing member 104. From the curved member 104, the chain assembly 26 passes over a drive sprocket or wheel 105 associated with the traction hoist assembly 22 and from this latter sprocket, the chain ex tends forwardly and around a third curved member 106, and from thence inwardly in reentrant fashion beneath the plate structure and around an arcuate face provided on a guide block 108 extending between the side members of the leg 46, downwardly along the inside edge of the vertical leg 44, around a guide block 110 similar to the block 108*, and finally, horizontally a short distance with the other end of the chain being attached as at 112 to an end of the forked link 94. The length of the chain is such that in its free state, a certain amount of slack will exist in the chain throughout the tortuous path which it follows and which has been described above. The chain 26 constitutes the sole suspension means whereby the lifter assembly proper 24 is supported from the traction hoist assembly 22, and when the traction hoist during any given lifting operation, is initially raised for coil-transporting purposes, the slack in the chain is taken up in the manner indicated in Figs. 1 and 2 so that the chain becomes taut around the various curved surfaces 102, 104,

106 and the blocks 103 and 110, thus exerting a considerable degree of pulling force on the forked link 94, and consequently, upon the movable jaw assembly 34 so that a powerful clamping action will obtain between the two jaws 32 and 34.

Referring now to Figs. 1 and 6, the traction hoist assernbly 22 involves in its general organization a casing structure 120 of open-ended, inverted, box-like design and including a pair of vertical extensions 122, across which there extends a lift pin -124 designed for cooperation with the lifting hook 12 of the crane structure. The casing or framework 120 includes a pair of supporting brackets 126 for an electric motor M2 having a motor shaft 128 operatively connected, through a slip clutch mechanism 130, to the input shaft 132 of a conventional worm and gear reduction mechanism 134 having an output shaft 136. The output shaft 136 carries a sprocket 138 which is connected by means of a chain 140 to a sprocket 142 carried on a drive shaft -144 rotatably journalled in the casing structure 120. The drive shaft has mounted thereon the previously mentioned drive sprocket '105 over with the chain 26 passes.

Operation of the apparatus In the operation of the coil lifting and positioning-incohanism 10, assuming that a coil 14, resting upon a supporting surface 146 as shown in Fig. 1 with the longitudinal axis thereof extending vertically, is to be picked up or lifted and transported to another location 'and'deposited on the supporting surface as indicated in 'Fig. 2 with its axis extending horizontally, the crane is operated to bring the mechanism 10 into vertical register with 'the coil 14 while the jaws 32 and 34 are substantially vertical- 1y aligned with a region of the cylindrical wall of the coil. The lifting hook 12 is lowered so that the jaws 32 and 34 may straddle the'coil wa'lla's illustrated in Fig. 1. Vertical register of the jaws 32 and 34 with the coil wall for operative clamping purposes is made possible by initially operating the motor M2 in one direction or the other, as the case may be, to cause the traction drive sprocket 105 to move or slide the chain, so to speak, over the upper portions of the sprocket until such time as the lifter assembly proper 24 assumes the position wherein it is illustrated in Fig. 1 with the leg 44 extending vertically and with the legs 46and 48 extending horizontally. The motor M1 is operated in such a manner as to rotate the feed screw-84 in a direction which will move the movable jaw 34 away from the fixed jaw 32 andthe motor M1 is maintained energized until such time as a sufiicientclearance is attained between the two'jaws to accommodate the thickness of the coil wall. Upon lowering of the assembly 24 over the coil 14, the upper end of the coil wall will abut against the lower horizontal edge of the leg 48, thus limiting the downward extent of move'mentof the assembly 24. Thereafter, the motor M1 is operated in a. direction to cause the movable jaw 34% move'toward the fixed jaw 32 until such time as the 'vv-all' of the coil 14 'is firmly clamped between the two jaws. At' this time, the torque limitirig clutch 74 will commence "to slip, but because of the relatively 'gre'at extent o'f gear re'ductionoifered by the worm redu'cer :72, a self-lbck'ingadtion will take-placewherein'the wall of the coil 14 is firmly clamped between the two jaws Thetorquelimiting clutch may be of any desired conventional construction, one such clutch suitable for the present purposes being shown anddescribed in a co-pending application of Louis G. Kaplamserial No. 782,762, filed on December 24, 1958, and entitled, Torque Limiting Clutch Assembly With Heat Dissipating and Lubricating Means.

' Immediately after the. two jaws 32 and 34 have been brought into clamping relationship with respect to the coil 14 under the control of the motor M1, the crane is operated to elevate the traction hoist mechanism 22 whereupon any slack which may exist in the chain 26 will be taken up and a powerful tension will be applied to the chain. The magnitude of such tension will be a trigonometric function of the angles involved in the triangle existing between the points of t-angency of the chain 26 with the curved surfaces 104 and 106 and the point of tangency of the chain in passing over the drive sprocket 105.

After the coil wall has thus been firmly clamped between the two jaws 32 and 34 andthe coil elevated from the supporting surface 146, the motor M2 is operated in such a manner as to cause the traction drive pulley to rotate in a counterclockwise direction, as viewed in Figs. 1 and 3, whereupon the driving sprocket will tend to run beneath the chain 26, so to speak, to the right as viewed in these figures. Inasmuch as the traction hoist 22 is supported 'onthe hook 12 and thus exerts a reaction force 'on the chain 26, the latter will be slid to the left,'as viewed in Fig. 1, and in so sliding, the chain 26will unwind, so to speak, from the verticalleg 44 and move against the horizontal leg 46 as the entire lifter assembly proper 24 turns bodilyabout an axis which, roughly, represents the center of gravity of the assembly.

At such time as the assembly 24 assumes a position I (tire assembly to the left, as viewed in Fig. 2, whereupon the jaws will move out of register with the coil walland the'coil will remain supported on the surface 146 in its horizontal position.

f t is to benoted at this point that while the assembly 24 is operatively suspended from the chain 26, the clan'rping action of the motor -M1, operating through the slip clutch or torque limiting device 74, isaugmented by -the degree of tension which is applied to the chain and which operates through the forked link 94 directly upon thetmrt or block 86 which constitutes an element of the movable jawas'sembly 34.

When it is desired to pickup andtransport a coil :14 which initially assumes a horizontal position on:the :supporting surface 146 and to' deposit it me 'verticalzposi tion at another location on such surface, a reversal :of the operations described above may be resorted 'to. *It is obvious that the lifter mechanism 10 of the ipresent invention may be employed 'forrece'i-vin-g coils which are disposed at any intermediate 'position as between the vertical position illustrated in Fig. l and the 'horizontal positionillustrated in Fig. 2 .and depositing :them intthe same or a different intermediate'position. f

While one specific form of the invention ihas been illustrated in the accompanying drawings and described in this specification, it'will he understood thatltli is form of lifting apparatus does not :by :any means Mindicat'e the only form :suitable for :upending ;o'r'aotherwise'ipositi'oning coils. For example it -is---contemplate.d: that insteadiof a roller I chain for :the I assembly 26am I otherrsui-table'ftform .of flexible supporting ;medium or element fmay be :em-

.ployed if desired. .The 'iformiillustrated herein is merely one which has been developed for commercial ap plication of the invention. The invention, therefore, is not to be interpreted as being limited to the details described since these may be modified within the scope of the appended claims without departing from the spirit of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In a lifter mechanism adapted to operatively receive an article supported at one location on a supporting surface in one predetermined position of orienta tion and transport the article to another location and deposit the same on a supporting surface at said latter location in a different predetermined position of orientation, said lifter mechanism comprising in combination a lifter assembly proper, a traction hoist assembly, and an interconnecting, elongated, linear, flexible suspension member between the lifter assembly proper and the fraction hoist assembly, said lifter assembly comprising a framework providing a fixed clamping jaw, a movable clamping jaw carried by said framework and movable toward and away from said fixed clamping jaw for articleclamping and article-releasing purposes respectively, a feed screw rotatably mounted on said framework and having a threaded connection with said movable clamping jaw, means including said threaded connection establishing a lost motion connection between said feed screw and said movable jaw whereby limited axial sliding movment of the movable jaw relative to the feed screw may take place independent of said threaded connection, a reversible motor mounted on said framework, a power train operatively connecting the motor and feed screw in driving relationship, said flexible member having one end thereof fixedly secured to said framework and having its other end secured to said movable jaw, the intermediate reach of the flexible member being normally slack, guide means for said intermediate reach of the flexible member whereby, upon application of upward lifting force to said intermediate reach at various points intermediate the ends of the flexible member, the latter will be drawn taut and a degree of tensioning pull will be applied to said movable jaw tending to move the latter toward said fixed jaw, said traction hoist assembly including a traction drive wheel underlying said intermediate reach of the flexible member and over which the flexible member is adapted to pass in opposite directions respectively, and a reversible motor operatively connected to said traction drive wheel in driving relationship.

2. In a lifter mechanism adapted to operatively receive an article supported at one location on a supporting surface in one predetermined position of orientation and transport the article to another location and deposit the same on a supporting surface at said latter location in a different predetermined position of orientation, said lifter mechanism comprising in combination a lifter assembly proper, a traction hoist assembly, and an interconnecting flexible chain assembly between the lifter assembly proper and the traction hoist assembly, said lifter assembly com prising a framework providing a fixed clamping jaw, a movable clamping jaw carried by said framework and movable toward and away from said fixed clamping jaw for article-clamping and article-releasing purposes respectively, a feed screw rotatably mounted on said framework and having a threaded connection with said movable clamping jaw, means including said threaded connection establishing a lost motion connection between said feed screw and said movable jaw whereby limited axial sliding movement of the movable jaw relative to the feed screw may take place independent of said threaded connection, reversible, motor mounted on said framework, a power train operatively connecting the motor and feed screw in driving relationship, said flexible chain assembly comprising a chain length having one end thereof fixedly secured to said framework adjacent one end thereof and having its other end secured to said movable jaw, the intermediate reach of said chain being normally slack and passing loosely around the other end of the framework and from thence passing in reentrant fashion toward said one end of the framework and loosely around said end, whereby, upon application of upward lifting force to said intermediate reach at various points intermediate the fixedly secured end of the chain and said other end of the chain, the chain will be drawn taut and a degree of tensioning pull will be applied to said movable jaw tending to move the latter toward said fixed jaw, said traction hoist including a traction drive sprocket underlying said intermediate reach of the chain and over which the chain is adapted to pass in opposite directions respectively, and a reversible motor operatively connected to said traction drive sprocket in driving relationship.

3. In a lifter mechanism adapted to operatively receive an article supported at one location on a supporting surface in one predetermined position of orientation and transport the article to another location and deposit the same on a supporting surface at said latter location in a different predetermined position of orientation, said lifter mechanism comprising in combination a lifter assembly proper, a traction hoist assembly, and an interconnecting flexible chain assembly between the lifter assembly proper and the traction hoist assembly, said lifter assembly comprising a framework providing a fixed clamping jaw, a movable clamping jaw carried by said framework and movable toward and away from said fixed clamping jaw for article-clamping and article-releasing purposes respectively, a feed screw rotatably mounted on said framework and having a threaded connection with said movable clamping jaw, the threads of said threaded connection loosely fitting each other and establishing a lost motion connection between said feed screw and said movable jaw whereby limited axial sliding motion of the movable jaw relative to the feed screw may take place independent of said threaded connection, a reversible motor mounted on said framework, a power train operatively connecting the motor and feed screw in driving relationship, said flexible chain assembly comprising a chain length having one end thereof fixedly secured to said framework and having its other end secured to said movable jaw, the intermediate reach of the chain being normally slack. guide means for said intermediate reach of the chain whereby, upon application of upward thrust to said intermediate reach at various points intermediate the ends of the chain, the latter will be drawn taut and a degree of tensioning pull will be applied to said movable jaw tending to move the latter toward said fixed jaw, said traction hoist assembly including a traction drive sprocket underlying said intermediate reach of the chain and over which the chain is adapted to pass in opposite directions respectively, and a reversible motor operatively connected to said traction drive sprocket in drivingrelationship.

4. In a lifter mechanism adapted to operatively receive an article supported at one location on a supporting surface in one predetermined position of orientation and transport the article to another location and deposit the same on a supporting surface at said latter location in a different predetermined position of orientation, said lifter mechanism comprising in combination a lifter assembly proper, a traction hoist assembly, and an interconnecting flexible chain assembly between the lifter assembly proper and the traction hoist assembly, said lifter assembly comprising a framework providing a fixed clamping jaw, a movable clamping jaw carried by said framework and movable toward and away from said fixed clamping jaw for article-clamping and article-releasing purposes respectively, a feed screw rotatably mounted on said framework and having a threaded connection with said movable clamping jaw, the threads of said threaded connection loosely fitting each other and establishing a lost motion connection between the feed screw and movable jaw whereby limited axial sliding of the movable jaw relative to the feed screw may take place independent of said threaded connection, a reversible motor mounted on said framework, a power train operatively connecting the motor and feed screw in driving relationship, said flexible chain assembly comprising a chain length having one end thereof fixedly secured to said framework and having its other end secured to said movable jaw, the intermediate reach of the chain being normally slack, guide means for said intermediate reach of the chain whereby, upon application of upward thrust to said intermediate reach at various points intermediate the ends of the chain, the latter will be drawn taut and a degree of tensioning pull will be applied to said movable jaw tending to move the latter toward said fixed jaw, said traction hoist assembly including a traction drive sprocket underlying said intermediate reach of the chain and over which the chain is adapted to pass in opposite directions respectively, and a reversible motor operatively connected to said traction drive sprocket in driving relationship.

5. In a lifter mechanism adapted to operatively receive an article supported at one location on a supporting surface in one predetermined position of orientation and transport the article to another location and deposit the same on a supporting surface at said latter location in a different predetermined position of orientation, said lifter mechanism comprising in combination a lifter assembly proper, a traction hoist assembly, and an interconnecting flexible chain assembly between the lifter assembly proper and the traction hoist assembly, said lifter assembly comprising a framework providing a fixed clamping jaw, a movable clamping jaw carried by said framework and movable toward and away from said fixed clamping jaw for article clamping and article-releasing purposes respectively, a feed screw rotatably mounted on said framework and having a threaded connection with said movable clamping jaw, the threads of said connection loosely fitting each other and establishing a lost motion connection between the feed screw and movable jaw whereby limited axial sliding of the movable jaw relative to the feed screw may take place independent of said threaded connection, a reversible motor mounted on said framework, a power train operatively connecting the motor and feed screw in driving relationship, said flexible chain assembly comprising a chain length having one end thereof fixedly secured to said framework adjacent one end thereof and having its other end secured to said movable jaw, the intermediate reach of the chain being normally slack and passing loosely around the other end of the framework and from thence passing in reentrant fashion toward said one end of the framework and loosely around said end whereby, upon application of upward thrust to said intermediate reach at various points intermediate the fixedly secured end of the chain and said other end thereof, the chain will be drawn taut and a degree of tensioning pull will be applied to said movable jaw tending tomove the latter toward said fixed jaw, said traction hoist including a traction, drive sprocket underlying said intermediate reach of the chain and over which the chain is adapted to pass in opposite directions respectively, and a reversible motor operatively connected to said traction drive sprocket in driving relationship.

References Cited in the file of this patent UNITED STATES PATENTS 1,818,584- Schroeder Aug. 11, 1931 2,627,109 Bock Feb. 3, 1953 2,629,625 Phillips Feb. 24, 1953 2,821,318 Kendall Jan. 28, 1958 OTHER REFERENCES Bellmann: German application B31,954 (K35b/603), printed May 24, 1956. 

